How Much Contingency Should a Renovation Budget Hold?

Fifteen percent on a like-for-like renovation, twenty percent where services or layout change, and twenty-five percent where structure is exposed or the building predates 1960. Below ten percent you are not holding a contingency, you are holding a hope.

Contingency is not padding and it is not the contractor’s margin. It is the money that lets you keep making decisions when the third surprise arrives, instead of accepting the cheapest fix because the budget is gone.

What does contingency actually pay for?

Discovered conditions: asbestos, failed joists, illegal wiring, a drain that goes nowhere, a wall that is not where the drawing says. All are invisible until demolition.

It also pays for the decisions that follow, which is the part people miss. A surprise is cheap to fix well and expensive to fix badly, and the difference is usually a few hundred pounds of contingency.

Why is ten percent not enough?

Because a single discovery in an older house routinely costs two to four percent of the contract value. Two discoveries consume a ten percent contingency before the finish is even ordered.

Statistics from renovation lenders consistently show that over half of projects exceed their initial budget, and the average overrun is well above ten percent.

Where should contingency sit in the budget?

As a separate line, held by the client, not absorbed into the contract sum. If the contractor holds it, it becomes scope rather than reserve.

Keep it in a separate account and draw on it deliberately. A contingency that sits in the current account gets spent on upgrades.

Does the age of the house change the figure?

Yes. Pre-1960 houses often have no damp proof course, older wiring, lath and plaster, and lead or asbestos in unexpected places. Twenty-five percent is realistic.

Post-1990 houses are more predictable, and fifteen percent is usually sufficient for a layout change.

What about a structural project?

Thirty percent is not unusual when a wall comes out, a basement is dug, or a roof is altered. The structural unknowns are the expensive ones and they cannot be surveyed from the surface.

A structural survey reduces the risk. It does not eliminate it, because a survey is a sample of the building, not a full inspection.

How does contingency interact with the schedule?

Time contingency and cost contingency are separate. An eight-week job should be programmed as ten, and a project can be on time and over budget or under budget and late.

Holding both is what keeps a project from turning a surprise into a crisis. Neither one covers the other.

Should contingency be spent on upgrades?

Only at the end, and only if it is genuinely unspent. Spending it mid-project on a better worktop is how people end up with no reserve when the boiler fails.

The rule that works: no discretionary upgrade until practical completion. Then the remainder is a bonus rather than a hole.

How is contingency tracked?

With a change log: date, description, cost, who approved it, and which budget line it draws from. The log is the difference between a controlled project and a conversation.

Review it weekly. A contingency drawn without a log entry is a cost that will reappear later.

Does a fixed-price contract remove the need?

No. A fixed price covers the defined scope. It does not cover what is behind the plaster, and most contracts exclude latent defects and unforeseen conditions.

Read the exclusions page. That page is where the fixed price ends and your contingency begins.

What counts as a legitimate draw?

Work that could not have been foreseen, or work required by an authority that could not have been predicted. Not a change of mind, and not an upgrade.

Classifying a change of mind as a contingency draw is how budgets fail without anyone noticing.

How much does the average kitchen overrun by?

Ten to twenty-five percent, usually through service upgrades, discovered damp and late changes. Bathrooms overrun by less in money and more in time.

The pattern is consistent enough that a fifteen percent line should be treated as standard, not cautious.

Can contingency be insured?

Not directly, but a latent defects policy covers structural problems discovered after completion, and a renovation warranty covers workmanship. Both are separate products.

Neither replaces a cash reserve during the build. Insurance pays later; contingency pays now.

What about a contingency on a very small job?

Ten percent minimum still applies, because a small job has less room to absorb a surprise. A 5,000 bathroom with a 3,000 discovery is not a small problem.

On a very small job, the better approach is to fix the price by specifying fully, then hold the contingency anyway.

How should the budget be presented?

Three columns: committed, forecast, and remaining. Add a contingency line and a change log, and review it weekly against the schedule.

A one-page budget reviewed weekly beats a spreadsheet reviewed once. The review is the control.

Does contingency cover delays?

Not directly. Delay costs money through extended rent, storage or alternative accommodation, and that should be a separate line if it applies.

Households living on site rarely cost out the disruption. It is real, and it belongs in the budget if the job runs long.

What is the most common way contingency disappears?

Small upgrades: a better tap, a larger tile, a different door. Each is a few hundred and together they consume the reserve before the structural surprise arrives.

Log every upgrade as a variation against the contingency, even the ones that feel trivial. The trivial ones are the aggregate.

How much should be held at the end?

Five percent retention until the snag list is closed and the certificates are in hand. That is separate from contingency and it is the client’s leverage.

Releasing retention before the certificate arrives is the most common reason a small defect becomes a large argument.

Does contingency cover the client’s own purchases?

Yes, and it should. Tiles, sanitaryware and lighting bought directly are the lines most likely to be underestimated and least likely to be covered by the contract.

Add a small allowance for breakages and short deliveries. Ten percent on tiles is standard, because cuts and breakages consume the extra.

What is the right way to think about it?

Contingency is the price of not knowing, and the price rises with the age and complexity of the building. It is not pessimism; it is the cost of the information you do not have.

Unspent contingency is a good outcome, not a wasted budget. The guide on staging renovation payments shows how to tie releases to milestones so the reserve stays intact.

Budget control is a weekly habit rather than a document. The guides on payment staging and on handling variations cover the two mechanisms that keep it working.